Soy-food consuming populations of people, like the
Chinese and Japanese, have a much lower incidence of heart disease,
osteoporosis, and cancer of the breast and prostate. From this
observation, many researchers have come to the conclusion that ingredients
in the soybean have anticancer, antihypertensive, and anti-cholesterol
benefits, and also act as a natural alternative to hormone replacement
therapy. Soy foods have become synonymous with health food and
vegetarianism. Their popularity is tied to the belief that soy has
“wonder-drug” benefits – so powerful that many people suppose they can
safely eat their bacon and eggs for breakfast as long as they finish off
their morning meal with a cup of soy yogurt.

We recommend that you use traditional soy foods, like
soy milk and tofu, only as a small part of your diet, at most 5% of your
daily calories. “Synthetic soy foods,” like meats, cheeses, and soy bars,
should rarely, if ever, be consumed.

Examples of sensible uses might be:

Soy milk to moisten cereal, not glassfuls as a
beverage

Tofu pieces in a “stir-fry” rice dish, not as a soy
burger entrée

An occasional tofu-based dessert, not daily soy
“candy” bars

However, there is a dark side to the soy story that
warns that these foods may increase your risk for cancer, impair your
thyroid, immune, and brain function, and cause you bone loss and
reproductive problems. Fortunately, these worries are relevant mostly for
people lured into consuming “fake foods” synthesized from man-made
components of soy and other foods, and high potency soy supplements – not
for those who consume traditional soy foods as a small portion of their
diet.

Soy’s Effects Are Usually Inconsequential

In Asian countries, soy is consumed as boiled soybeans (edamame),
tofu (soybean curd), natto (fermented soybeans), miso (fermented soybean
paste), okara (a by-product of tofu), soybean sprouts, soymilk, yuba
(by-product of soy milk), kinako (soy flour), and soy sauce. These foods
are made from simple processes like grinding, precipitation, and
fermentation – thus, most of soy’s ingredients remain little altered. Less
than 5% of daily calories in the typical diet of Japanese or Chinese
people comes from soybeans.1 This amounts to about 2 ounces (55 to 64
grams) derived from soy foods daily, which means only 7 to 8 grams of
protein and 15 to 45 milligrams of the estrogen-like phytochemical known
as isoflavone. How could this tiny amount of soy food make a measurable
difference – positive or negative – to the health of Asians?

The primary reason these people are so hardy is that the
Asian diet is based on a starch – rice – with generous amounts of
vegetables and fruits. Starches are ideal foods for human nutrition and
have many desirable nutritional qualities – they are low in fat, moderate
in protein, high in carbohydrates, and contain no cholesterol. The Asian
diet also contains few animal products. Any unique pharmacologic benefits
from eating soy are unnoticeable compared to the impact of these people’s
overall diet. (For a discussion of the benefits of starches, see my April
2004 newsletter article: People – Not Their Words – Tell “The Carbohydrate
Story.”)

Soy – Detrimental or Beneficial

The truth behind soy is clouded by emotional reactions
from the anti-soy movement of hard-core meat-eaters and soy-loving
vegetarians – and as usual, money from big businesses, the soy
manufacturers. Most of the rhetoric on both sides of the argument is of no
real importance – the real issue is whether you are consuming small
amounts traditional soy foods or making yourself a diet of synthetic
foods.

The Seven Main Arguments:

Argument 1: Anti-nutrients

Detrimental: Soy contains “anti-nutrients,” which
interfere with the digestion of proteins (trypsin inhibitors) and the
absorption of minerals (phytic acid).

Beneficial: These “anti-nutrient” substances are
deactivated by cooking and fermentation. Cooking before consumption is not
unique to soybeans – no other beans, peas, or lentils are eaten “raw.”
Although adverse effects on experimental animals have been demonstrated,
there is no direct evidence as to the physiological effects of the trypsin
inhibitors on humans.2 Interestingly, Phytic acid has anticancer effects
in animal models for both colon and breast cancer.3

Argument 2: Cancer

Detrimental: Soy has estrogen-like activity that may
promote the growth of estrogen-sensitive cancers (breast and prostate),
especially for those people who already have cancer.4-5

Beneficial: Breast and prostate cancer rates are four to
six times lower in Japan and China than Western countries. In laboratory
studies, isoflavone from soy can inhibit the growth of breast cancer and
prostate cancer tissues.6

Argument 3: Heart Disease

Detrimental: Benefits on heart disease are largely
unproven and are really due to the low-fat, low-cholesterol qualities of
the Asian diet.

Beneficial: People living in countries with more soy in
their diet, for example Japan, have a much lower risk of heart attacks.
Experimental research consistently shows soy foods cause a decrease in
total and “bad” LDL cholesterol, and an increase in “good”
HDL-cholesterol.7-8 Products containing at least 6.25 grams of soy protein
per serving are now allowed to carry a FDA-approved claim on their label;
stating a low-fat, low-cholesterol diet containing at least 25 grams
(about one ounce) of soy protein a day may reduce one’s risk of heart
disease.

Argument 4: Sex Hormones

Detrimental: Twelve ounces of soy milk drunk three times
a day for one month will decrease a woman’s estradiol and progesterone
levels, and her menstrual cycle length will be increased by about four
days.9 These effects may cause infertility and contribute to bone loss.

Beneficial: Chinese and Japanese are among the most
prolific baby-makers in the world. Phytoestrogens have both a weak
estrogen-stimulating (estrogenic) and paradoxically, an
estrogen-inhibiting (anti-estrogenic) activity. The estrogen-like
activities may strengthen bones and prevent menopausal symptoms like hot
flashes. Hot flashes are reported by 70% to 80% of US menopausal women
compared to 10 to 14% of women in Japan and Singapore.10 The anti-estrogen
activity reduces the risk of breast and uterine cancer.

Argument 5: Thyroid

Detrimental: Goiter and hypothyroidism have been
reported in infants receiving soy formula. Autoimmune diseases of the
thyroid and thyroid cancer may also be caused by exposure to soy.11-12

Beneficial: The addition of adequate iodine to the diet
reverses any goiter-causing effects of soy. Population studies suggest soy
protects against thyroid cancer.13

Argument 6: Immune System

Detrimental: In experimental studies, soy isoflavone
suppresses the immune system, and reduces the size of the thymus gland.
There are reports of a decrease in antibodies, white blood cells, and
other indications of immune system malfunction with soy consumption.14-19

Beneficial: Soy isoflavone enhances the immune response
and provides a possible explanation for lower incidence of certain cancers
in soy-eating parts of the world.20,21 The pain of arthritis has been
helped by soy through modulating the immune system.22

Argument 7: Brain Health

Detrimental: A recent study of middle-aged
Japanese-Americans living in Hawaii found adults consuming tofu had
reduced brain function, accelerated brain aging and some structural
changes in their brains that might be related to Alzheimer’s disease.23

Beneficial: Alzheimer’s disease and other forms of
dementia are less common in Asian compared to Western populations.24
Recent studies have actually shown improvement in brain functions with the
use of soy supplements.25,26

In summary, population studies fail to support real-life
soy-caused diseases, experimental data is inconsistent, and the larger
components of the diet (starches, vegetables, and fruits) are most likely
the reason for the superior health of soy consuming peoples.

The Whole Is Healthier Than the Parts

Over the past two decades there has been an explosion on
the supermarket shelves of soy products that resemble our favorite meat
and dairy products. I often refer to these as “fake foods.” Manufacturing
processes remove the dietary fibers, carbohydrates, fats, vitamins,
minerals, and hundreds of other helpful plant chemicals – leaving behind
almost pure soy protein.

These protein concentrates are mixed with extracts of
wheat protein, vegetable oils, and sometimes, starch, sugar, salt,
artificial sweeteners, and dairy and egg proteins – then the magic of
modern technology turns these mixtures into products that look and taste
like real cheese, hot dogs, sausages, burgers, luncheon meats, chicken,
and turkey. Soy protein is used to replace dairy protein in candy bars,
yogurt, ice cream, breads, pastries and cookies. You can identify the
synthesized concentrated proteins on the ingredient list of your foods by
these words: defatted soy flour, organic textured soy flour, textured
vegetable protein, isolated soy protein, soy protein concentrates, and soy
concentrates. These new “foods” in no way resemble nature’s creations and
the effects on your health make that clear.

Calcium Loss and Cancer Growth from Protein
Concentrates

Concentrated dairy (cow-milk) protein, when consumed by
people, causes large and important loses of calcium contributing to
osteoporosis and kidney stones. You would hope that replacement with soy
protein concentrates would eliminate this health hazard. Unfortunately,
recent research on people has demonstrated that the addition of 40 grams
of concentrated soy protein to a diet, already low in protein (40 to 50
grams daily) and high in calcium (1100 mg daily), causes significant net
losses of calcium from the body.27 Other research shows isolated soy
protein is just as damaging as meat protein to the bones.28

Another recent study showed how 40 grams of soy or
cow-milk protein concentrate added to the diet significantly increases
levels of a powerful cancer-promoting growth hormone, called Insulin-like
Growth Factor 1 – IGF-1.29 However, soy protein was almost twice as
powerful as the milk protein concentrate – doubling the levels of IGF-1
with 40 grams of soy protein isolate. This growth promoter has been
strongly linked to the development of cancer of the breast, prostate,
lung, and colon.30 Excess IGF-1 stimulates cell proliferation and inhibits
cell death – two activities you definitely don't want when cancer cells
are involved. 30

What does 40 grams of isolated soy protein mean to you?
In real life, a person seeking excellent health by following a low-protein
version of the McDougall diet with 1100 mg of calcium (which would have to
be added with a calcium supplement) becomes at risk for osteoporosis,
kidney stones, and cancer with the daily addition of a soy “candy bar” and
a soy shake. One soy “chicken” patty for lunch and 2 soy burgers for
dinner will also add that 40 grams of isolated protein daily – and so will
just four soy breakfast patties. Now soy has real meaning in your life.

The effects of adding soy protein concentrates on people
already consuming the bone-losing, high-animal-protein Western diet (100
to 160 grams of protein daily), or worse yet, the Atkins diet (up to 300
grams daily) have yet to be determined.31 Because of the very low
incidence of osteoporosis, and breast and prostate cancer, among people
who consume traditional soybean foods, there is every reason to believe
that only the synthetic soy foods need to be of concern. (Studies have yet
to be done to specifically test the effects of traditional foods in
laboratory settings – in the meantime, we will keep these as a small part
of our diet.)

Many of these foods
also contain an isolated wheat protein (gluten) which has similar
effects on calcium loss.32

Pharmaceutical-grade Soy Hormones

Phytochemicals found in plants are important ingredients
for radiant health, but must be consumed in their natural packages – like
the traditional soy foods – to reap the most benefits with the least
risks. After isolation from their natural environment – the soybean –
these chemicals unquestionably become pharmaceuticals.

Manufacturing processes concentrate the pharmacologic
ingredients of soy into powerful drugs sold to women to treat menopausal
symptoms and osteoporosis. Unfortunately, drugs have side effects. A
concentrated preparations of isoflavone, sold as Novasoy®, and mixtures of
the active chemicals (isoflavone and/or genistin), have been shown to be
strong promoters of breast cancer growth in animals.33 Long-term treatment
(up to 5 years) with soy isoflavone preparations was associated with an
increased occurrence of endometrial hyperplasia in women – a precancerous
condition of the female uterus.34

Soy Infant Formula

Soy baby formula is synthesized from pure sugar (corn
syrup), oil (safflower), and protein (soy protein isolate) – this is the
epitome of “fake food” – especially when considering the potential
consequences. Approximately 1.4 million (36%) infants per year in the
United States receive soy formula. Because 100% of the dietary protein and
isoflavone that the baby gets is from soy, the chemical compounds reach
levels many times higher than the levels found in adults who consume soy
foods – and even exceed concentrations shown to be toxic in laboratory
experiments. For example, daily exposure to estrogen-like compounds from
soy formula results in levels 6 to 11 times higher in infants than the
level that will cause changes in the menstrual cycle of women.35-36

The reason so little is known about the harmful effects
of feeding soy formula to babies is that these effects in real life
situations have not been adequately studied. However, some indication of
the sensitivity of a baby to soy’s estrogen-like effects might be learned
from a recent study finding birth defects of the genitalia of male infants
(hypospadia) born to mothers who consumed large amounts of soy products.37

Reserve Traditional Soy foods for Special

Despite concerns, there is no definite evidence that
traditional soy foods are harmful at levels customarily consumed. Consider
the hundreds of millions of people living in Japan, consuming soy products
throughout their life – and they enjoy the longest life expectancy in the
world (Japanese women are expected to live 84.93 years, compared to US
women to 79.5 years; and Japanese men to 78.07 years, compared to 74.1
years for US men).

However, soybeans and their by-products should be
thought of as rich foods – naturally high in fat and protein. In their
traditional forms consider them as delicacies – and you should consume
them as you might other plant food delicacies – nuts, seeds, avocados, and
olives – in small amounts on special occasions.

Soybeans Are
Nutritionally between a Bean and a Nut

These soy items
are rich plant foods (look at the fat and protein contents)

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The Meat Free Zone (MFZ) campaign is intended to make the MeatFreeZone logo as
recognizable a symbol as the "Smoke Free Zone". The idea was originally
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as it was the first cruelty-free, Vegan, socially conscious animal rights store
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growing so rapidly, more and more people are showing concern about the food in
their diet and their overall health and nutrition. Many people are giving up
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ice cream) and eggs. Headlines of Mad Cow disease, E-coli
and salmonella are in the news with greater frequency. Vegan and vegetarian
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